Movable coil for electrical measuring-instruments



(No Model.)

B. WESTON. MOVABLE 0011. FOR ELECTRICAL MEASURING INSTRUMENTS. No. 470,340. Patented Mar. 8, 1892.

WITNESSES. 6 m YEN-TOR M M ATTZMH.

UNITED STATES PATENT OEEIcE.

ARD WESTON, OF NEWARK, NEW JERSEY.

MOVABLE COIL FOR ELECTRICAL MEASURING-INSTRUMENTS.

SPECIFICATION forming part of Letters PatentNo. 470,340, dated March 8, 1892.

Application filed March 11, 1891.

To a whom it may concern.-

Be it known that I, EDWARD WEsToN, of Newark, Essex county, New Jersey, have invented a new and useful Improvement in Movable Coils for Electrical Measuring-Instruments,of which the following is a specification.

In Letters Patent No. 433,637, dated August 5, 1890, and in other Letters Patent granted to me I have described an electrical measuringinstrument in which there is a stationary coil and a movable coil supported therein, which movable coil is in circuit with a stationary coil, and therefore assumes a position due to the reaction of the two fields surrounding said coils when they are traversed by a current, which position depends upon the difference in potential existing between the terminals of, an instrument. The instrument in question is more particularly intended for the measurement of alternating currents. In order to render the apparatus sensitive, it is necessary to make the movable coil as light as possible, both to reduce the inertia of the coil itself and its dead-weight upon the delicate jewelpivots by which it is supported.

Mypresent invention has for its object this reduction in weight of the coils; and to this end I make the coil entirely of insulated wire, using no spool or bobbin or frame for its support.

In the accompanying drawings, Figure 1 illustrates the method of making the coil. Fig. 2 is a side view of the completed coil.

Similar letters of reference indicate like parts.

In order to make a coil, I take a former or mandrel, as A, and wind thereon a layer of thin insulated wire, bringing the turns of the wire close togetherand making a layer a of a width equal to the width of the finished coil.

I then apply to the wire an exterior coating Serial No.384=,654=. (No model.) I

b of shellac varnish, and then immediately wind a second layer of wire upon the first. A second coating of varnish is then applied and a third layer of wire wound, and so on until the coil is made of the requisite thickness. The wire is Wound under proper tension and all parts are closely compacted together, and are thus held by any suitable means until the varnish is dry. The mandrel A is then removed, when it will be found that the coil is a hard compact annular mass, exceedingly strong and light. Upon opposite sides of the coil I attach light plates B, of aluminium or copper, which carry suitable pivot-pins, as O, and to these plates the terminals of the coil maybe connected. The plates B are secured in place by seizings D of thin silk.

In lieu of shellac I may use any other suitable cement, and by changing the shape of the former A, I may make the coil of any desired form.

I claim 1. An insulated coil-conductor having numerous turns cemented together to form a compact annular body and provided with pivots, substantially as described.

2. An insulated coil-conductor having numerous turns cemented together to form a compact annular body and provided on opposite sides with pivots to which the terminals of said coil are respectively connected, substantially as described.

3. An insulated coil-conductor having numerous turns cemented together to form a compact annular body, in combination with plates B, carrying pivot-pins O, substantially as described.

EDIVARD IYESTON.

Witnesses:

R. C. FESSENDEN, A. F. CONERY, Jr. 

